Mold for sub stabilizers



June 16, 1942.

E. J. CLARK MOLD FOR sub STABILIZERS Filed March 5, 1941 V INVENTOR. Erna-s5 (I: Clank Patented June 16, 1942 TAT E A E 6 Claims.

The present invention relates generally to What are known in the oil well tool industry as Kelly stabilizers, commonly in the nature of a preformed, cylindrical rubber protector to be seated in an annular groove of the Kelly sub intermediate the ends of the latter, and to be held, by virtue of the seating groove, against displacement lengthwise of the sub.

The use of pre-formed, cylindrical rubber protectors around various portions of a drill stem, as buffers against the internal surface of the casing, is well known in drilling by the rotary method. Such protectors are commonly expanded onto the sections of drill pipe and permitted to retract thereon between the end collars thereof. They are also expanded onto the Kelly sub and there permitted to retract into the annular grooves with which Kelly subs are commonly provided. In the latter use the protectors are known as Kelly stabilizers, and in both uses the protectors project materially beyond the outer surfaces of that portion of the drill stem on which they are used.

On drill pipe the protectors or buffers are, of course prevented from displacement by the end collars of the pipe, but it is well known that the Kelly sub has no end collars and that the groove .of the sub often fails to hold its stabilizer properly in place. The frequent necessity for replacement of the stabilizer on the Kelly sub is a source of annoyance, involving the loss of valuable time on the rig in the drilling operations.

Since the protector as used on the Kelly sub has an important function in stabilizing the Kelly bar in the drilling operation, it is with the foregoing in mind that the present invention primarily aims to avoid frequent, vexatious replacement of such stabilizers, by molding the same in and around the sub groove to bring about such firm, uniform adherence of the stabilizer with the sub as to endure, without danger of displacement, the rigors of continued use.

The invention arises from the discovery that a stabilizer of tough lasting rubber may be formed according to this invention by vulcanization on the sub to so adhere to the latter within its groove as to defeat accidental displacement in use, by bufling the surface or surfaces of the sub within its groove, and utilizing the sub as a means of internally applying heat to the rubber during vulcanization, at the same time heat is applied externally thereto by means of an external shaping and heating mold.

It is necessary that a substantial portion of the stabilizer extend materially beyond the external surface of the sub, and that its ends be bevelled in order to avoid substantial engagement with portions of the well equipment going in or coming out of the hole, and the invention comprehends not only a stabilizer in non-displaceable adherence with the sub, but also the external shaping and vulcanizing mold therefor, and the method by which it is employed for the desired purpose in combination with the heated sub.

With the foregoing in mind, the further objects and resulting advantages of the invention may be better understood and more thoroughly appreciated in the course of the following detailed description thereof, or rather of a preferred form thereof, and by reference to the accompanying drawing, which forms one part of this specification, and in which,

Figure 1 is a View, partly in elevation and partly in section, showing a Kelly sub and the adjacent connected portions of the Kelly bar and drill pipe.

Figure 2 is an enlarged sectional view lengthwise through the Kelly sub and through the stabilizer and mold with the parts in position during the operation of vulcanizing the stabilizer in the sub groove.

Figure 3 is a transverse sectional view through the parts of Figure 2, taken substantially on line 2-2 of said figure.

Figure 4 is a fragmentary side view of the mold, :l'lOWlng the mold latch in closed, effective posiion.

Figure 5 is a detail perspective view of one of thei clamping and mold centering rings or plates, an

Figure 6 is a similar view of the mold body, showing the parts in open position, removed from the sub.

Referring now to these figures, and particularly to Figure 1, I have shown the lower portion of the Kelly bar I0, with its usual pin H threaded into the upper box end of a Kelly sub l2 whose lower pin end I3 is of a size or diameter to conform to that of the drill pipe M in use, it being understood that different subs I2 with smaller or larger lower ends may be used so that any desired size of drill pipe can be readily coupled to the lower end of a standard size kelly bar.

Figure 1 also shows the Kelly sub I2 as provlded, at a point intermediate its ends, with an annular groove it which, according to the present invention has its bottom and end surfaces buffed or otherwise thoroughly prepared by cleaning for the adherence of rubber thereto, during vulcanization of such rubber from an unvulcanized state in which it is placed in the groove.

For the above purpose, the groove 5 may have the usual square end walls It, as seen in Figure 1, or these end walls may be undercut as indicated at I! in Figure 2.

Remembering that the groove l5, however shaped in the above respect, is formed in that portion of the sub I 2 which, like the Kelly bar It, is of standard diameter, and that the sub has a bore I8 which, in use, forms a part of the drilling fluid feed channel I!) to the drill string, the groove I5 is, subsequent to the above described preparation of its surfaces, filled with unvulcanized rubber for the formation of the stabilizer 2|], either With or without internal fabric or other reenforcement 23 After the unvulcanized rubber has been built up in the sub groove to a desired point outwardly beyond the surface of the sub, a shaping and vulcanizing mold, preferably of the form and construction shown in Figures 2 to 6, inclusive, is placed therearound. This vulcanizer is shown as comprising two semi-cylindrical sections 2| and 22, each hollow and provided with steam inlet and outlet pipes or connections 23 and 24. The closed ends of these sections are formed to snugly and flatly abut one another, and may be clamped to each other at one or both ends by the clamping arrangement best seen in Figures 3, 4 and 6.

The clamping arrangement referred to may be used at both ends of otherwise unconnected mold sections 2| and 22 or, as shown, the mold sections may be clamped at but one end, and connected at their opposite ends by a hinge or hinges 25. In either event the clamping ends may be assured of true alinement in their meeting relation, by means of guide lugs 26 on one of the sections, arranged to embrace and overlap the other section, when the sections are closed.

The clamping device also preferably includes a grooved keeper lug 2! on one mold section, having recessed side wings 28, and a clamping lever 29 pivotally mounted at one end thereof on the other section. Intermediate the ends of lever 29 there is pivotally connected thead-jacent end of a toggle lever or bar 35, whose opposite end portion is threaded for the reception of an adjusting nut 3| limiting movement of a slidable engaging head 32 having diametrically outstand ing trunnions 33.

The trunnions 33 are adapted to interfit the wing recesses of the keeper lug 2'1 when the toggle bar 39 is in the keeper groove as in Figures 3 and 4, to thus effectively lock the mold sections 2| and 22 around the unvulcanized rubber.

To center the mold with respect to the sub I2, it will be noted that the mold sections 2| and 22 have laterally projecting stud bolts 3 which, when the sections are clamped together, register with the openings 35 of a pair of ring-shaped side plates 35. The inner perimeters of the plates 35 snugly fit the outer surface of the sub l2, onto which they are positioned from its opposite ends. In so doing, as in the entire vulcanizing operation, it will be understood that the sub is detached from both the Kelly bar and the drill pipe so that the opposite ends are free and the ends of its bore I3 are exposed.

After association of the end plates 35 on the stud bolts 34 so that they abut, as for instance by means of their inner cylindrical extensions 36, the mold rings 3! shown around the sub l2 and within the mold sections 2| and 22, it is obviousthat the unvulcanized rubber will be confined within the centered mold and between the mold rings 37, for the shaping and formation of the finished stabilizer with bevelled end walls for that portion thereof extending beyond the outer surface of the sub l2. For this purpose the rings 37 have the inwardly facing bevelled surfaces as shown.

The rings 37 are thus engaged by the inner surfaces of the mold sections 2| and 22, and pressed thereby snugly against the surface of the sub I2, and in order to hold the said rings for shaping the ends of the stabilizer, and at the same time permit of yielding thereof in a lengthwise direction, coil springs 38 are disposed on the stud bolts 34 and placed under compression by nuts threaded on the said bol'is, as at 3%, the inner ends of the said springs yieldingly pressing the end plates 35 closely against the ends of the mold sections as plainly seen in Figure 2.

Thus, with the mold associated properly, and as described, around the sub l2, its above mentioned parts not only insure its true co-axial relation with the sub l2, but also insure that the mold rings 37 will yieldingly support and shape the rubber so as to form the ends of the stabilizer with true bevelled surfaces. It is to be noted that, since the end plates 35 act to space the mold sections around the surface of the sub in the position for vulcanization, they control the pressure of contact of said mold sections against the mold rings 3! so that the latter may easily take care of any surplus rubber during the vulcanizing operation.

With the molding arrangements in place as described, steam is fed to the cavities of the mold sections 2| and 22 through the feed pipes 23 for continuous circulation through these sections and return therefrom by way of the outlet steam pipes 23, to thus vulcanize the rubber and cure the same to the very tough, Wear resistant consistency necessary on account of the severe conditions of its use.

In the vulcanization of the rubber, it is a highly important feature of the invention to utilize the sub i2 itself as a means of applying vulcanizing heat to the stabilizer from the inside thereof. To do this suitable plugs 40 may be fitted into the opposite ends of the bore |8 of the sub, with steam pipes 4| and 42 opening into the said bore through the plugs. One of these pipes may serve to feed the steam to the bore I8 for circulation through the bore and for outlet through the other pipe. By thus utilizing the sub itself as a means of applying heat to the interior of the rubber during vulcanization, and the mold sections as a means of applying heat from the exterior, thorough, efficient conditioning of the rubber is assured.

It will be understood, of course, that various modifications and changes may be made in the several parts as described and shown, among which may be mentioned the substitution of electrical heating coils in the mold sections 2| and 22, and in the sub l2, for the steam heating arrangements, since it is primarily important that they be properly heated without regard to the particular heating medium. This is merely an example of modifications and changes which maybe made so long as the essential characteristics, to which attention has been previously called, are maintained, it being obvious that the molding of the protector or stabilizer in place may be accomplished on any portion of a cylindrical drill stem by the method and means of the present invention.

Having thus fully described the invention, what is claimed is:

1. A stabilizer shaping and vulcanizing mold, comprising mold sections arranged for disposition around a Kelly sub for the vulcanizing of a stabilizer on the sub, means in connection with the mold sections for spacing the same from, and centering the same around, the sub, means for clamping the mold sections to each other, and mold rings in spaced relation to each other within the mold sections, and yieldably supported by said first named means for movement lengthwise of the mold sections.

2. A stabilizer shaping and vulcanizing mold, comprising mold sections, means for clamping said sections to one another around a stabilizer forming body of unvulcanized rubber, mold rings within and around the mold sections in spaced relation lengthwise of the latter, and means in lengthwise yielding connection with said mold sections at the opposite sides thereof for centering the same around a Kelly sub, and having portions thereof abutting and controlling lengthwise movement of said mold rings.

3. A stabilizer shaping and vulcanizing mold for Kelly subs, comprising mold sections, means for clamping said sections to one another around a stabilizer forming body of rubber on a Kelly sub, mold rings within and around the mold sections in spaced relation lengthwise of the latter, end plates in lengthwise yielding connection with the opposite side portions of said mold sections and having portions extending inwardly of said sections for centering the latter around the sub, said portions engaging the mold rings and forming yielding limits to movement of the rings toward the respective ends of the mold.

4. Stabilizer shaping and vulcanizing means including the molding means as set forth in claim 2, in combination with means for heating the mold, and means for internally heating a sub within the mold.

5. A stabilizer shaping and vulcanizing mold for Kelly subs, comprising mold sections having laterally projecting stud bolts, means for clamping said mold sections to one another, end plates having apertures through which said bolts may be extended when the mold sections are clamped together, and having portions extending inwardly of the mold sections for centering the latter around a Kelly sub, mold rings within the mold sections and movable lengthwise thereof against the last mentioned portions of the said end plates, and means for adjustably anchoring the said end plates including spring means on at least one side of the mold sections around the stud bolts thereof and engaging the respective end plate for yieldingly supporting the latter and the respective mold ring.

6. A cylindrical stabilizer mold for disposition around a Kelly sub, comprising semi-cylindrical mold sections, means for clamping said sections in endwise abutting relation, stud bolts projecting from the sides of said sections at spaced points therearound, centering plates having openings for receiving said bolts when the mold sections are clamped together, nuts on said bolts beyond said plates, springs around the bolts between said nuts and said plates for yieldingly urging the plates toward the mold sections, and mold rings interiorly of the mold sections having movement lengthwise of the mold and yieldingly limited by said centering plates.

ERNEST J. CLARK. 

